1. Field
The present invention relates to irrigation and crop supplement application devices and more particularly to fertigation devices in which a supplement is suspended in irrigation water.
2. State of the Art
Crops are an important component of feeding the world""s population, by direct consumption such as wheat, corn, and rice, and by indirect consumption by eating animals which have directly consumed the crops. Growing crops uptake water and dissolved minerals in order to grow and sustain themselves by photosynthesis. However, the amount of water available for irrigating crops is diminishing each year in many areas due to the encroaching populations of people which compete for water and changes in precipitation due to global weather changes such as global warming.
In ancient times prior to such shortages of water, irrigation was typically conducted by utilizing aqueduct and irrigation ditches between the crops to bring water from distant lakes and other such water reservoirs. More recently with the advent of pressurized water systems, spray systems were developed which are movable such as drip tape, drips, emitters, micro-sprays, sprinklers on hand lines as well as by rolling on wheels to irrigate crops. Some methods of irrigation waste considerable amounts of water due to evaporation and run-off of water which does not reach the roots of the plants.
Crops must typically be fertilized and treated with soil amendments and insecticides routinely for proper growth. This may be done by spraying fertilizers, insecticides, soil amendments, and other crop supplements (hereinafter referred to as supplements) on the crops, which is done between irrigation periods, requiring extra water to be used. A technique called fertigation was developed which utilizes the irrigation water to distribute supplements. Fertigation is the most effective method of applying supplements to crops. Fertigation is a process of injecting supplements in the prescribed amount and at a specific time into the water stream during the irrigation process. Compared to conventional ground application, fertigation also improves supplement efficiency. Therefore, comparable or better crop yields and quality can be produced using twenty to fifty percent less supplement. Farmers using irrigation and fertigation have greater control over available water and also over the supplements supplied to the crop. Fertigation satisfies a need for greater efficiency by improving the return from each unit of input. Utilizing these irrigation systems to apply plant supplements offers growers the most efficient method for placing supplements in the root zone. Fertigation is fertilization via the irrigation system and is the most advanced and efficient practice of fertilization. Fertigation combines the two main factors in plant growth and development, which are water and supplements. The right combination of water and supplements is the key for high yield. The most efficient fertigation practice is to supply supplement in small regular applications. This allows the plant to be xe2x80x9cspoon fedxe2x80x9d and receive supplements, as it needs them, in a form of broad acre hydroponics. This also prevents valuable supplements from being leached from the soil profile before the plant has had a chance to use them. Supplement ratios can also best satisfy the need of the plant throughout the growth cycle.
The benefits of fertigation include: 1) uniform application in the form of uniform distribution and precision placement of supplements and other chemicals; 2) timely application wherein the materials can typically be applied regardless of weather or field conditions; 3) reduced application costs such that the cost of application is about one-third the cost of conventional application methods; 4) improved crop management using timely applications of small but precisely delivered amounts of supplement directly to the root zone allows growers to effectively manage supplement programs, which conserves supplement, saves money, and optimizes yield and quality; 5) reduced soil compactation by reduced tractor and equipment traffic in fields; 6) minimizes exposure of workers to chemicals through reduced operator handling, mixing and dispensing of potentially hazardous materials with people and non-target crops not being exposed to inadvertent chemical drifts; 7) reduced environmental contamination when fertigation devices used are properly designed and calibrated including having the recommended safety devices to help preserve the quality of the environment; 8) marginal farming areas can be fertilized after the crops have emerged from the ground rather than adding supplement prior to crop emergence and wasting money on unused supplement.
University studies have provided a guide to correct fertigation techniques, which includes: 1) growers must water and fertilize uniformly; and 2) growers must determine: a) which supplement formulations are most suitable for injection into the irrigation water system; b) the most appropriate analysis for specific crops at specific stages of growth; c) the amount to apply during a given fertigation event; and d) the timing and frequency of applications.
In most situations, fertigation is as good or better than conventional application methods. However, conventional application may still be preferred or required for some materials and/or situations. One should never inject any material that is not labeled and recommended to the crop and for injection through the system. Fertigation can save time, reduce labor and equipment requirements and conserve energy and materials. However, fertigation is beneficial only to the extent that the irrigation system is adequately designed, fully functional and properly managed.
Most types of highly water soluble supplements and liquid supplements are suitable for fertigation. Additionally, attempts have been made to use conventional granular supplements, but with limited success primarily due to settling out of undissolved particles and the lack of an efficient delivery system to inject the particles into the irrigation water. Examples of attempts to introduce a granular substance such as gypsum into water for the purpose of fertigation include U.S. Pat. Nos. 5,765,945 and 5,681,109 both issued to Palmer. Therein are disclosed respective apparatus and method for hydraulically adding the powderous substance or a liquid to a water system such as an irrigation ditch. The substance is held in a container provided with a screened lower zone and supplied with a water sprayer. The water sprayer deposits water on the interior surface of the screen which essentially dissolves the powderous substance present at and which passes through the screen. The slurry produced can be delivered to an irrigation ditch, creek, or the like. While the apparatus may work for highly soluble powderous substances, less soluble powderous substances such as gypsum, which requires fifty gallons of water to dissolve one pounds of gypsum tend to settle out in the apparatus and in the associated outlet pipes producing partial clogs and complete blockages.
There is a need for a fertigation delivery system which utilizes conventional supplement formulations which eliminates settling out of undissolved particles and which efficiently injects the particles into the irrigation water.
The present invention comprises a dry supplement injection system, a dry supplement injection irrigation system, a continuous feed dry supplement injection system, a micronized particulate composition for use in the dry supplement injection systems, and a method of introducing a dry supplement into a flow of irrigation water.
The dry supplement injection system is connectable to a water supply for supplying water under pressure to produce a slurry from supplements in a micronized form to be used in fertigation application that may contain both dissolved and undissolved supplements which is introduced into a flow of irrigation water for watering crops. The dry supplement injection system includes a dry supplement injection device having a main hopper which includes an outer wall defining a main hopper chamber, an upper portion having an inlet opening, and a lower portion having an outlet opening. A perforated funnel assembly is disposable within the chamber and includes an inverted, perforated funnel having a perforated outer wall defining a funnel chamber, a small upper opening, and a large lower opening. A vertically disposed inlet pipe extends through the upper opening and is affixed to the funnel with at least one spray nozzle fluidly connected to the pipe being disposed within the funnel chamber to spray water onto the wall of the perforated funnel. An inlet water pipe system includes a main pipe that connects to the water source through the wall of the main hopper to the inlet pipe and the spray nozzle wherein water discharged from the spray nozzle impinges on the perforated wall of the perforated funnel such that particles of micronized supplement are washed through the perforated funnel forming a slurry. An outlet water pipe system includes a slurry pump which draws slurry formed in the main hopper and passed through the outlet opening through a slurry pump inlet pipe and pumps the slurry under pressure through a slurry pump outlet pipe into an irrigation water pipe through which the flow of pressurized irrigation water flows for irrigating the crops. The slurry pump may be eliminated for use with non-pressurized irrigation water conduits.
The dry supplement injection irrigation system is connectable to a water supply for supplying water under pressure to produce a slurry from supplements in a micronized form to be used in fertigation application that may contain both dissolved and undissolved supplements, and for introducing the slurry into a flow of irrigation water and spraying onto crops. The dry supplement injection irrigation system includes a dry supplement injection device of the type described above, and an irrigation device to which the injection device is connectable having an irrigation water pipe through which the flow irrigation water flows for irrigating the crops.
The continuous feed dry supplement injection system is connectable to a water supply for supplying water under pressure to produce a slurry from supplements in a micronized form to be used in fertigation application that may contain both dissolved and undissolved supplements which is introduced into a flow of irrigation water for watering crops. The continuous feed dry supplement injection system includes a dry supplement injection device of the type described above, and a motorized feed screw assembly. The motorized feed screw assembly includes a feed screw hopper for receiving the micronized supplement, and a motorized feed screw which includes an inclined outer tube having an inlet connected to a lower outlet of said feed screw hopper and which is upwardly inclined from the feed screw hopper to an outlet disposed above the inlet opening of the main hopper. A feed screw closely fits within the outer tube and is rotationally driven by a motor. The micronized supplement enters the outer tube through the inlet thereof and is transported through the outer tube by the feed screw to the outlet and into the main hopper for production of slurry therefrom.
The micronized particulate composition is for use in the dry supplement injection systems, and includes a plurality of particles of at least one material, wherein at least fifty percent and preferably between about ninety-five to ninety-nine percent of the particles are smaller than about 74 microns (200 mesh) in size for producing the slurries.
The method of introducing a dry supplement into a flow of irrigation water includes the steps of: 1) providing a dry micronized supplement; 2) producing a slurry of the micronized supplement and water, which slurry may contain both dissolved and undissolved particles of the micronized supplement, by spraying water at an interior surface of an inverted perforated funnel which separates the dry micronized supplement from an interior chamber of the funnel; and 3) pumping the slurry produced into a flow of irrigation water for watering crops.